1.样品与测定 样品采自剖面中20个主要层次。 全剖面深39.7米,埋藏有5层古土壤(S_1～S_5)。古土壤粘化层色红,其1～4层厚0.5～2.3米,第5层厚7.1米,由三条挨近的古土壤组成,通称“红三条”。5层古土壤由6层黄土(L_0～L_5)间隔。且每一条古土壤的下层均有一条明显的淀积层(C_1～C_5),呈强烈的石灰性反应。L_0以上为马兰黄土,以下为离石黄土。分析了L_D 1. Samples and Determination Samples were taken from 20 major sections in the section. The whole section is 39.7 meters deep and 5 layers of ancient soil are buried (S_1 ~ S_5). Ancient soil sticky color red, 1 to 4 layers of 0.5 to 2.3 meters thick, the fifth layer of 7.1 meters thick, composed of three adjacent ancient soil, commonly known as “red three.” Five layers of paleosol are separated by 6 layers of loess (L_0 ~ L_5). Each of the ancient soils had an obvious sedimentary layer (C_1-C_5) in the lower layer, showing a strong calcareous reaction. Above L_0 is Malan loess, the following is Lishi loess. Analyzed L_D